Radio frequency systems commonly employ dual-path devices as building blocks for various tasks such as signal routing, combining and monitoring. Examples of dual-path devices include dual-path amplifiers, such as balanced or Doherty amplifiers.
One issue with such dual-path devices is close physical proximity of adjacent elements. For example, in some dual-path amplifiers the wire bonds for the two inputs of the two paths can have close physical proximity. Likewise, the wire bonds for the two outputs of the dual-path amplifier can have close physical proximity. In any of such cases, the close physical proximity of the adjacent wire bonds can induce magnetic coupling between the adjacent wire bonds. Such induced magnetic coupling can degrade the performance of the dual-path amplifier. For example, the induced magnetic coupling can displace the impedance at the inputs of the device, and thus limit the RF performance.
As one specific example, the magnetic coupling between wire bonds can shift the impedance in a way that is dependent upon the phase difference between signals carried on the two paths in the dual-path device. Such a phase difference can further result in a gain variation along one path that is dependent upon the phase difference, and thus can cause RF performance degradation.